The present invention relates to a coating apparatus, and more particularly to an apparatus for applying coating material to a strip of metal or other substrate. More particularly, the present invention relates to a dispenser unit for a coater apparatus for applying liquid coating material to a strip of metal or other substrate.
Coating apparatus are disclosed in U.S. Pat. Nos. 4,604,300, 5,549,752, 5,985,028, and 6,013,312. These references are hereby incorporated by reference herein.
Currently, numerous methods exist for applying a coating or thin film of material to a strip of metal or other material. One conventional method of coating a continuous strip of substrates to submerse the strip in a bath of the coating material. This can be accomplished by pulling the substrate through the bath of coating material, and then wiping off any excess coating material. This method has many drawbacks. One drawback to this method is the difficulty to control the amount of coating material applied to each side of the strip. Another drawback is the inability to apply different coating materials to each side of the strip. Also, this method often wastes a certain amount of the coating material during the wiping step.
Another known method of applying a coating or thin film of material to a strip of substrate is to employ a spray coater or atomizer. In such a method, the coating material is electrostatically disposed on the strip. A spray coater in accordance with this method is disclosed in U.S. Pat. No. 4,839,202.
Other known types of coating methods include passing the strip of substrate through various applicators which deposit a thin film onto the strip with or without electrostatic assistance. The applicators can be either stationary members or rotable members. One example of such a coating apparatus, which uses a pair of oppositely-disposed applicators, is disclosed in U.S. Pat. No. 5,549,752 to Hahn et al. The Hahn patent discloses passing a continuous strip of material between a pair of oppositely disposed applicators for applying a thin film thereto. In one embodiment, two stationary wicks directly contact the sides of the continuous strip of material to apply a coating to both sides of the sheet material. In another embodiment, the wicks apply the coating material to two feed rolls which contact the sides of the strip to apply a thin film of coating material thereto. One drawback to this type of coating apparatus is that it lacks the ability to adjust the amount of coating material being supplied to various sections of the applicators.
Other examples of prior coating apparatuses and methods are disclosed in U.S. Pat. Nos.: 5,985,028 to Cornell et al.; 4,601,918 to Zaman et al; 4,604,300 to Keys et al.; 4,712,507 to Helling; and 4,995,934 to Janatka.
There is a need to provide a coating apparatus that increases efficiency and reduces waste. Accordingly, it is an object of the present invention to provide a coater for a coater apparatus that includes a dispenser unit having a coating discharger strip for dispensing coating material that can be replaced quickly and easily. It is a further object of the present invention to provide such a coater wherein the dispenser unit includes an anti-wicking member for increasing efficiency and decreasing waste.
In accordance with these and other objects, the present invention provides a coater for applying coating material to a moving strip of metal or other substrate. The coater comprises at least one dispenser unit, and preferably a pair of dispenser units disposed about the moving strip of substrate. Each dispenser unit is adapted to be in communication with a supply of coating material and to apply coating material to a side of the moving strip. Each dispenser unit comprises a receptacle, a coating discharger strip received within the receptacle having an applicator surface for applying coating material to the respective side of the moving strip, a retainer member received within the receptacle for securing the discharge strip within the receptacle, and an anti-wicking member associated with the retainer member for hindering wicking of coating material away from the applicator surface of the coating discharger strip. Each dispenser unit desirably also includes at least one adjustable element associated with the retainer member for adjustably positioning the retainer member within the receptacle to secure the coating discharger strip to the receptacle for applying coating material to the side of the strip.